Evaporator for refrigerating apparatus of the compression type



Sept. 29, 1942. R. HINTZE ETAL EVAPORATOR FOR REFRIGERATING APPARATUS OF THE COMPRESSION TYPE Filed Feb. 3, 1939 5 Sheets-Sheet 1 M4 m 2! 0w M M as Se t. 29, 1942. R.. Hm'rzE ETAL EVAPORATOR FOR REFRIGERATING APPARATUS OF THE COMPRESSION TYPE Filed Feb. 3. 1939 S SheetS-Sheet 2 29, 1942. I R. HINTZE Er-AI.

EVAPTJRATOR FOR REFRIGERATING APPARATUS OF THE COMPRESSION TYPE 3 Sheets-Shee t 3 Filed Feb. 5, 1939 Patented Sept. 29, 1942 EVAPORATOR roa REFBIGEBATING AP miner-us 0! TH Commission ma F in the Alien Proper y Application In February 3, 19.39; Germany February udolf Hintse, nerlln cliariottenburg, and Peter Pfaif, Beriin-siemensstadt, Germany;

custodia No. 254,460 a, loss- Y 10mm; {01.62-126).

- The present invention relates-to improvements in evaporators for refrigerating apparatus of the compression type. U

Evaporators for refrigerating apparatus of the compressionv type are frequently made of two metal sheets secured face on' facetogether by welding and provided with indentations servin as conduits and as a collecting tankor header for the refrigerant. The welded sheets are as arule so bent that they form aconipartment for J0 freezing purposes, for instance for the reception of ice trays. A suction conduit leading to the compressor of the refrigerator is connected to.

the refrigerant collecting tank orheader formed by the metal sheets. An object of the present invention is to improve the operation and reliability of evaporatois of the above-mentioned titude of parallelqarrangedbranches does not take place at thelowest point of the evaporator.

Consequently, the refrigerant vapors developed to a relatively slight extent at the lowest point of the evaporator pass through all conduits of the evaporator, since, when using only two or a few parallel evaporator'branches, the failure'of one conduit reduces the eflective' evaporaton surface to such an extent that the pressure of evaporation is considerably reduced, thus causing the noneifective evaporator branch to'come again into operation.- This effect does not occur in evap-.

. orators with a large number oi parallel-arranged evaporator conduits, because the failure of one branch to operate does not influence the piessure of evaporation to such an extent as to reestablish the proper operation of the evaporator.

type without incurring difliculties, or additional costs-when manufacturing the evaporator structure. Other objects will become apparent from: the following description.

According to the invention, the indentations and corrugations of the two welded metal sheets 1 which form the main structure ofthe evaporator, are so arranged inthe bent structure that the refrigerant supplied to the lower part of the evaporator is conveyed to the collecting header along a path not extending in the downward direction. This arrangement prevents the .for-

mation of vapor pockets in the refrigerant pas- An evaporator according to the invention may contain a single. sinu'ous'conduit as above described as the only connection between the lowest point of the evaporator to the collecting tank. Another form of the invention is so designed .that

sages formed in the metal sheets. 'As compared with such known types of evaporators in which a single helical evaporator coil is employed, the

evaporator according to the invention presents the advantage that the vaporous refrigerant developed in the evaporator can always easily rise to the collecting header unimpeded'by vapor pockets which may occur inthe said 'coil evaporators.

Another known construction contains a manifold arranged at the lowest pointof the evaporator, which is supplied with refrigerant and j from whence it passes into a header through a number of conduits extending in parallel relation in the upward direction and forming the two side walls of the evaporator. This construction prevents the formation of vapor pockets. However, its parallel conduits are liable tb clog up so that. it may happenthat only some of the parallel conduits are effective in producing cold.

In contradistinction thereto, the evaporator" structure according to the invention is so de-. signed that, the refrigerant passes from the low-' est point of the evaporator to the collecting tank through only one or a fewsinuous conduits so the refrigerant .passes from the bottom portion ofthe' evaporator at first through a single sinuous refrigerant conduit to a manifold and thence through two or more parallel'conduits to the collecting header.

' Another form of the invention employs two evaporator sections each having a horizontal surface for the reception of ice trays. Each of the two sections has a sinuous refrigerant conduit. leading to a common header. The two surfaces serving for the reception of ice trays are preferably so. arranged that they lie at different heights. The liquid refrigerant is supplied from a control valve, for instance a float valve, to the lower part of the evaporator preferably through a short. conduit.

The vaporous refrigerant carried off fro the header through asuction' conduit may stil contain liquid refrigerant together with the entrained lubricant. It therefore is preferable not to extend this conduit directly to the suction 'side of the compressor, butto'interpose. an additional evaporator in which the residual liquid refrigeraiit may evaporate. This additional evaporator is preferably designed according to the invention as a sinuous conduit formed by the abovementionedcorrugations of the sheet metal strucmatic form.

that a distribution of the refrigerant over a multure composing the evaporator. I

. In the accomp nying drawings are shown severai embodiments of the invention in diagram- Fig. 1 represents a front view an evaporator according to the invention, while 'II. is provided in metal'sheets I and l of structionin front view and one of the sheet metal I elements used for its manufacture, respectively.

Figs. '7 and 8 show a front view of a third type ofconstruction as well'as one of its'sheet metal elements, respectively.

Fig. 9 exemplifies a fourth way the invention, also by showing a front view of the complete evaporator structure, and I of embodying Figs. IQ and 11 show the two indented'metal sheets used in this embodiment The evaporator shown in Fig. 1 is made of two metal sheets I and Isecured, face on facetogether, by welding. In the metal sheet i, shown developed in Fig. 2, are formed sinuous corrugations and indentations forming a conduit 3 and a collecting tank or header 4 for the refrigerant. A supply conduit 6 is connected to the lowest point of the evaporatorfor supplying liquid refrigerant from the float valve (not shown). a-a, b-b and c-c denote the lines. of the evaporator about which the two metal sheets are to be bent in order to form the box-like structure of Fig. l. A conduit I leading to the suction side of the compressor is connected to the collecting tank 4. As will be.readi1y apparant, the

refrigerant conduit 3 forms a passage in which the vaporous refrigerant may at all times easily rise into the collecting tank 4 without permitting the formation of vapor pockets. In Fig...1 the collecting tank 4 is. for instance, bent in the upward direction in such a manner, as indicated at 0-0, that the liquid refrigerant entrained into the header] bythe rising gas bubbles may completely flow back into the evaporator winding 3.

In Figs. 3 and 4, like reference numerals denote like parts as shown in-Figs. land 2. In Fig. 3

arcane taining the additional evaporator and the other evaporator parts 23, respectively, a recess the evaporator.

The twoembodiments shown in Figs. Ho 11 .are of a type in which two evaporator sections, each consisting of a sinuous refrigerant conduit.

are connected to a common collecting tank 4. each of the evaporator sections having a horizontal surface serving for the reception of ice trays. In the case of the evaporator shown in Figs.-7'=and 8. the refrigerant is conveyed through a conduit 34' to a manifold II, and thence through a straight supply duct 32 to the lowest point It of'the surface for the reception of the upper ice tray. The horizontal part of the surface is provided with a sinuousrefrigerant conduit 34 which. extends to the collecting tank 4 through the evaporator part shown at the right-hand side of .Fig. 'l. A corresponding refrigerant supply duct 35 leads to the lowest point II of the surface for the reception of the lower ice tray. The lower horizontal portion and the perpendicular wall portion of the sheet metal structure shown at the left-hand side of Fig. 'l, are provided with asinuous refrigerant conduit 31. which also extends to the collecting tank 4. 44 denotes the suction conduit connected to the collecting tank 4. h-h, i-i, lc-'-lc, l-l denote the bending edges of the evaporator. I

The evaporator shown in Figs. 9 to 11 is formed of the two metal sheets 4i and u. The liquid refrigerant is supplied to the evaporator through the-conduit 4'. The sinuous refrigerant conduit 7 tending to the lower part of the collecting tank,

' 4 isconnected tothe end 4|; of the; sinuous pasthe refrigerant is suppliedat a into the sinuous conduit ll arranged in the lower horizontal por tion-of the evaporator. One end of this sinuous conduit II is designed in the form of a manifold.

To the latter are connected three parallel ducts I! which convey the refrigerant around the bending edge 0-0, after which the refrigerant passes into the collecting tank 4 through two sinuous es la and I4, and ducts ll.

In the form of the-invention shown in Fig. 4

straight supply duct 22 to the lowest pointll' of the sinuous evaporator conduit II which e'xtends over the lower horizontal wall section. of the evaporator chamber, the left-hand vertical wall sectionand the upper horizontal wall section of the evaporator structure to the header 4. The refrigerant leaves the collecting tank 4 at 24 and passesthroughthe straight conduit 24 into a sinuous refrigerant conduit 20 serving as an additional evaporator. This conduit 24 forms the perpendicular right-hand wall section of the evaporator.. To the end 21 of the conduit "is connected a conduit 2| leading to the suction side, of the compressor. 'The bending edges of the evaporator plates are denoted by lo-d. 1-! and H. To reduce the direct heat exchange between the. two sections of the structure consage 41. ll denotes"; the suction conduit and try-1n, rt-n, H denote the bending edges of the metal sheets 4| and 42.

The additional evaporator shown in Figs.'5 and i 6 may also be employed in a corresponding manner in. the forms of the invention shown in the other figures.

What is claimed is:

' 1. An evaporator structure for compression refrigerators, comprising two metal sheets sealed face to face together, one of said sheets having ing two horizontal sections spaced vertically from supplied, from aplpe-n ending at 2i, through a each other so as to form two separate spaces for deep-cooling purposes, each of said horizontal sections containing an individual sinuous conduit forming part of said conduit system, separate conduits also forming part ofsaid system and connecting said horizontal sections respectively with said collecting header, saidlatter conduits forming a refrigerant path nowhere extending in a downward direction. and. conduit means also forming part of said system for supplying refrig erant to each of said'horizontal sections.

2. In an evaporator for compression refrigerators composed of two metal sheets welded face to face together, at least, one of said sheets having indentations and corrugations so as to form together with said other sheet a collecting header and a conduit system communicating with said header, said header being arranged in the cen-- tral portion of said composite sheet structure whereby said structure forms two evaporator sections at either side of said header, each of said sections having a lower horizontal portion serving as. carrier for ice trays and an upper and mainly vertical portion, each of said horizontal portions containing a single sinuous conduit forming part of said conduit system, said upper portions containing conduits also forming part of said system so as to connect said horizontal sections with said header by passages nowhere extending in a downward direction, and conduit means also forming part of said system for supplying refrigerant to each of said horizontal portions. 1

3. In anevaporator for compression refrigerators composed of two metal sheets welded face to face together, at least one of said sheets having indentations and corrugations so as to form together with said other sheet a collecting header and a conduit system communicating with said header, said welded sheets being bent to a boxshaped structure forming a storage space for deep-cooling purposes and having a horizontal bottom section, said horizontal section containing a single sinuous conduit formingpart of said conduit system and communicating with said header through other parts of said conduit system so as to form a continuous passage from the lowest section of said structure to said header nowhere extending in a downward direction, inlet means arranged near said header for supplying refrigerant, and a straight supply duct connecting said inlet means with said sinuous conduit, said duct being also formed by corrugations of said metal sheets.

4. An evaporator structure for compression refrigerators, comprising two metal sheets sealed face to face together and having indentations and corrugations forming a collecting header and a conduit system respectively, said sheets being bent so as to form horizontal and vertical wall sections of a storage space for deep-cooling purposes, said conduit system formed by said corrugations having two separate branches, one oi said branches having a portion confined to one section of the evaporator structure and the other branch having a portion located in another section of said structure, said metal sheets having a recess separating said two sections, one of said branches of said conduit system consisting of a sinuous winding extending from the lowest section of the evaporator structure to the bottom portion of said header along a. path nowhere extending in a downward direction, said other branch consisting. of a sinuous conduit connect- ,ed with the top portion of said header and having an outlet to be connected with the compressor of the refrigerator, and a supply duct also formed by said corrugations, said duct having an. inlet opening near said header and being connected storage chamber for deep-cooling purposes, at

least one of said sheets having corrugations forming said evaporator conduit system and at least one of said sheets having an indentation forming a collecting header arranged above and com-' municating with said system. said corrugations forming said conduit system extending consequently over said horizontal and vertical wall sections along a path nowhere extending in a downward direction and including a single sinu- "ous passage forming the only connectiombetween said supply conduit and said header and extending over the horizontal wall section formin the bottom of said chamber;

6. Inan evaporator structure for compression refrigerators comprising an evaporator conduit system proper and a short supply conduit connected with the lowest portion of said system, a pair of metal sheets sealed face-to-face together and bent so as .to form horizontal and vertical wall sections of a storage chamber for deep-cooling purposes, said sheets having corrugations and indentations forming said evaporator conduit system and a collecting header arranged above storage space and' having one end forming they only connection "with said supply conduit, and a group of conduits arranged in parallel relation as regards the flow of refrigerant and extending substantially only over the vertical and upper wall sections of said chamber, said conduits of said group having one end'connected with said header and the other' end connected with the other end of said single winding so as to form a manifold connection, said composite passage forming a path nowhere extending in a downward direction.

7. In an evaporator structure for compression refrigerators comprising an evaporator conduit system prop errand a' short supply conduit connected with the lowest portion of said system, a pair of metal sheetssealed face-to-face together and bent so as to have horizontal and vertical sections forming the walls of a storage chamber for deep-cooling purposes, said sheets having corrugations and indentations forming said evaporator conduit system and a collecting header arranged above and communicating with said system, said corrugations forming said conduit system extending consecutively and continuously over said horizontal and vertical sections along apath nowhere extending in a downward direction and including a single sinuous passage forming the only connection between said supply conduit and said header and extending over substantially the entire wall section forming thebottom of said chamber, said pair of metalsheets having further corrugations forming an additional evaporator conduit 01' sinuous shape having one end connected with the top portion of said header and the other end forming the outlet of the evaporator structure.

'RUDOLF HINTZE.

PE'iZ'Ellt PFAFE. 

